The short version of tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-26 and is reviewed periodically as new material appears.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
Reversed-phase high-performance liquid chromatography is the standard approach for assessing purity, usually with ultraviolet detection near 214 nm, where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the molecular mass and helps reveal truncation or deletion byproducts. Amino acid analysis can verify composition, and counterion content is sometimes measured because peptides purified with trifluoroacetic acid retain variable amounts of that salt. Purity figures reported without a stated method and detection wavelength are difficult to interpret.
Material sold for research use varies widely in documented quality. A useful verification package includes a certificate of analysis that states peptide content rather than only net weight, the chromatographic method and column used, and a mass spectrum consistent with the expected mass. Independent testing by a third-party laboratory is occasionally reported. Statements of identity resting only on a supplier label provide little assurance, and the gap between nominal mass and actual peptide content can be substantial once counterions and residual water are counted.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
=== Unhappy marriage and divorce === Unhappily married couples suffer 3–25 times the risk of developing clinical depression, leading to divorce. Studies found that divorce and separation increases chances of an individual encountering depression, anxiety, substance abuse issues, insomnia, and financial hardship. Divorce and unhappy married couples not only affect the mental health of both the parents, but particularly the children of a separated home. Children of divorced parents engage in early sexual behavior, academic difficulties, substance abuse, depressive moods, and an increased chance of living in poverty due to family instability.
The melanocortin 4 receptor (MC4R) is a G protein-coupled receptor involved in regulating energy homeostasis, appetite, and sexual function. It plays a key role in metabolic processes and it predisposes to certain forms of obesity in humans. MC4R is a receptor that is activated by α-melanocyte-stimulating hormone (α-MSH), influencing energy homeostasis and feeding behavior in the central nervous system. In mouse models, MC4R has been shown to regulate feeding behavior, metabolism, reproductive function, and erectile response.
Later work making use of molecular evidence, with or without the use of morphological evidence, had by 2000 failed to resolve the argument. In 2011, on further molecular evidence, Janies and colleagues noted that the phylogeny of the echinoderms "has proven difficult", and that "the overall phylogeny of extant echinoderms remains sensitive to the choice of analytical methods". They presented a phylogenetic tree for the living Asteroidea only; using the traditional names of starfish orders where possible, and indicating "part of" otherwise, the phylogeny is shown below. The Solasteridae are split from the Velatida, and the old Spinulosida is broken up.
4-Acetoxy-N,N-dimethyltryptamine (4-AcO-DMT or 4-acetoxy-DMT), also known as O-acetylpsilocin or psilacetin, is a psychedelic drug of the tryptamine family related to psilocybin and psilocin. It is a synthetic derivative of psilocin (4-HO-DMT) in which the hydroxyl group has been acetylated, and is the analogue of psilocybin (4-PO-DMT) in which the phosphate ester has been replaced with an acetate ester. The drug is a prodrug of psilocin and is used orally similarly to psilocybin. As a prodrug of psilocin, 4-AcO-DMT acts as a non-selective serotonin receptor agonist, including of the serotonin 5-HT2A receptor. The hallucinogenic effects of psilocin are thought to be mediated by activation of this receptor, although other receptors also contribute to its effects. 4-AcO-DMT's effects are reported to be similar to those of psilocybin and psilocybin mushrooms. However, it has been said to have reduced side effects such as nausea and body load that can be caused by ingestion of whole psilocybin mushrooms. It is also said to have a faster onset and shorter duration than psilocybin. The drug is not expected to differ from psilocybin or psilocin in terms of safety. 4-AcO-DMT is modestly less potent by weight than psilocybin in animals when they are given at equimolar doses. 4-AcO-DMT was first described in a patent by Albert Hofmann in 1963 and its chemical synthesis was improved by David E. Nichols and colleagues in 1999.
Supplementation with formula is associated with decreased rates of exclusive breastfeeding at 6 months, and overall decreased length of breastfeeding. In terms of what to supplement with, the first choice is always the mother's own breastmilk, save any medical contraindications to its use. The second best option for supplementation is pasteurized human donor milk. Finally, specific formulas may be used for supplementation if maternal or donor breastmilk is not an option. One situation where this may be the case is in cases of infant metabolic diseases, such as galactosemia. The Academy of Breastfeeding Medicine recommends that supplementation only be used when medically indicated and when overseen by a medical professional, such as a pediatrician or family physician, and after consultation with an IBCLC. Without sufficient breast stimulation, supplementation can reduce the mother's milk production, so pumping would be indicated in these cases if continued breastfeeding is desired. Indications for use of donor breastmilk are very closely outlined by the American Academy of Pediatrics (AAP). Due to low availability and high cost of donor breastmilk, the AAP recommends prioritizing the use of the milk for infants born with a weight of less than 1500g (approximately 3lb 5oz), as it is helpful in decreasing rates of the severe intestinal infection, necrotizing enterocolitis, in this population.
Sources: en.wikipedia.org
The symptoms of myasthenia gravis developed within 6 days to 16 weeks (median time 4 weeks). Their medicine-induced myasthenia gravis symptoms were often severe with 29 people developing respiratory failure that required mechanical ventilation. Other studies have reported that these checkpoint inhibitors cause respiratory failure in 45% and death in 25–40% of people with myasthenia gravis. Statins: Statins are drugs that lower blood cholesterol levels in order to reduce the risk of developing a cardiovascular disease due to atherosclerosis. In a 2019 review of 169 people who were reported to develop myasthenia gravis or had worsened myasthenia gravis symptoms while taking a statin, 138 had developed generalized myasthenia gravis, 13 had developed ocular myasthenia gravis, and 18 had worsening of their myasthenia gravis. Following discontinuance of the statin and treatment of their myasthenia gravis, 63 people fully recovered, 27 people were recovering, 19 people had not yet recovered, 5 people recovered but had ongoing symptoms, 1 individual had died, and there was no follow-up data for 54 people. Among these cases, 56% were considered to be serious. A 2024 study evaluated 593 people who had myasthenia gravis and 790,399 people who did not have myasthenia gravis after being treated with a statin. The statin-treatment caused small but statistically significant increases in numbers of exacerbations of myasthenia gravis as well as new onsets of myasthenia gravis in people without the disorder.
==== 200–299 ==== Local Authorities (Standing Orders) Regulations 1993 (S.I. 1993/202) Furniture and Furnishings (Fire) (Safety) (Amendment) Regulations 1993 (S.I. 1993/207) Coal and Other Safety-Lamp Mines (Explosives) Regulations 1993 (S.I. 1993/208) Poultry Meat (Hygiene) (Amendment) Regulations 1993 (S.I. 1993/209) Liverpool Housing Action Trust (Area and Constitution) Order 1993 Approved by both Houses of Parliament S.I. 1993/210) Education (Designated Institutions in Further Education) (Wales) Order 1993 (S.I. 1993/215) Non-Domestic Rates (Scotland) Order 1993 (S.I. 1993/216) Superannuation (Children's Pensions) (Earnings Limit) Order 1993 (S.I. 1993/220) Insolvency Practitioners (Amendment) Regulations 1993 (S.I. 1993/221) Taxes (Interest Rate) (Amendment) Regulations 1993 (S.I. 1993/222) Drainage Rates (Forms) Regulations 1993 (S.I. 1993/223) Foreign Compensation (Financial Provisions) Order 1993 (S.I. 1993/224) Aircraft and Shipbuilding Industries (Repeals) (Northern Ireland) Order 1992 S.I. 1993/225) District Electoral Areas (Northern Ireland) Order 1993 (S.I. 1993/226) Parliamentary Constituencies (Wales) (Miscellaneous Changes) Order 1993 (S.I. 1993/227) Academic Awards and Distinctions (Queen Margaret College) (Scotland) Order of Council 1993 (S.I. 1993/230) Air Navigation (Third Amendment) Order 1993 (S.I. 1993/231) Local Government Finance Act 1992 (Community Charge Benefit) Savings and Transitional Order 1993 (S.I. 1993/232) Funds for Trade Union Ballots Regulations (Revocation) Regulations 1993 (S.I.
=== Helmholtz === The model dubbed the 'electric double layer' was first introduced by Hermann von Helmholtz. It assumes that a solution is only composed of electrolytes, no reactions occur near the electrode which could transfer electrons, and that the only Van der Waals interactions are present between the ions in solution and the electrode. These interactions arise only due to the charge density associated with the electrode which arises from either an excess or deficiency of electrons at the electrode's surface. To maintain electrical neutrality the charge of the electrode will be balanced by a redistribution of ions close to its surface. The attracted ions thus form a layer balancing the electrode's charge. The closest distance an ion can come to the electrode will be limited to the radius of the ion plus a single solvation sphere around an individual ion. Overall, two layers of charge and a potential drop from the electrode to the edge of the outer layer (outer Helmholtz Plane) are observed. Given the above description, the Helmholtz model is equivalent in nature to an electrical capacitor with two separated plates of charge, for which a linear potential drop is observed at increasing distance from the plates. The Helmholtz model, while a good foundation for the description of the interface does not take into account several important factors: diffusion/mixing in solution, the possibility of adsorption on to the surface and the interaction between solvent dipole moments and the electrode.
The Khmer Ceramics & Fine Arts Centre, formerly known as the National Centre for Khmer Ceramics Revival (NCKCR), is an organization aiming to rediscover and reintroduce Khmer ancestral pottery techniques and support the development of contemporary Khmer ceramics art. In the process, the centre creates economic opportunities, helping to decrease poverty in Cambodia. It is located in Siem Reap.
Sources: en.wikipedia.org
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
The powder is normally kept at −20 °C or below in a sealed, moisture-protected container. Letting the vial reach room temperature before opening helps prevent condensation on the contents.